1. Field of the Invention
The subject of this invention is a layout of a blisk that can be used in a turbine or a turbomachine compressor, for example.
2. Description of the Related Art
It is conventional that blades are provided with bulbs engaged in grooves notched into the disk, which hold the blades in place on the disk despite centrifugal forces that occur during operation. The grooves may be oriented along the axis of the disk and each may contain a bulb, or they may be circular and contain all the bulbs. The bulbs usually comprise oblique upper faces that bear on overhanging faces with the same obliqueness as the groove when centrifugal forces are applied. Inclinations of the groove relative to a median plane are sufficient so that no jamming occurs between these faces when centrifugal forces have ceased.
The invention is based on a wish to build some blades from a composite material such as CMC (Ceramic Matrix Composite). The difficulty that then arises is that the method of manufacturing by casting, compulsory for these materials, prevents excessive discontinuities in the orientation and therefore makes it essential that the inclination of the upper part of the bulb connected to the outer part of the blade in the radial direction should not exceed about 30°, while the inclination of the faces overhanging the groove has to be at least 40° to prevent jamming. Therefore, such blades cannot be directly integrated into a disk. The invention overcomes this problem.